Current collecting device



Patented Aug. 11, 1936 UNITED STATES PATENT oFFic-E 2,050,401 v 7 CURRENT COLLECTING DEVICE Pennsylvania Application February 23, 1933, Serial No. 658,096

9 Claims.

My invention relates, generally, to currentcollecting devices for electric vehicles and it has particular relation to slider shoes which are used for engaging a conductor. 7

With the advent of trackless trolley buses and greater speeds of electric vehicles which operate upon tracks, it has been necessary to redesign the current-collecting equipment so that a minimum of weight may be used, in order to obtain more satisfactory operation of these electric vehicles. Particularly in the use of current-collecting equipment for trackless trolley buses, it is desirable to have extremely lightweight currentcollecting equipment for the reason that the trolley poles used for supporting the currentcollecting equipment are of exceptional length, ranging from to 25 feet. It is thus apparent that it is necessary to apply a considerable force at the base of the trolley pole in order to provide the desired contact pressure between the current-collecting apparatus at the end of the pole and the current conductor, which, in many cases, is of the order of to 40 pounds. It is further apparent that it is highly desirable to reduce the weight of the current-collecting apparatus mounted at the extreme end of the pole to a minimum.

In order to obtain the lightweight construction of current-collecting equipment mounted at the end of long trolley poles, the customary wheel has been dispensed with and in place thereof a slider shoe is substituted. It has been found that .the slider shoe not only materially decreases the weight of the current-collecting equipment but also thatit reduces the Wear on the conductor, and, further, reduces to a considerable extent the problem of conducting the current from the elementin contact engagement with the conductor-to thepower circuit connected to the electrical apparatus in the vehicle.

The slider shoes that have been used in the .past have not been entirely satisfactory for the reason that they were relatively short-lived due to the fact that the relatively high abrasive forces exerted by the slider shoe travelling along the conductor served to rapidly'wear' it out. In order tocompensate for this rapid wear, it has been proposed to harden certain parts of the slider shoe or to cast the slider shoe around inserts of relatively hard material. However, slider shoes of these types are relatively expensive to manufacture and necessitate very careful construction "and machining in order to provide a satisfactory slider shoe. If these improvements are not reembodiment hereof shown in the accompanying sorted to, it is necessary to manufacture theslider shoe, using a relatively great quantity of material so that the relative Wear will be inappreciable. This, however, increases the weight of the current-collecting equipment, and certain of 5 the advantages of the slider shoe over the customary trolley wheel are lost.

It is, therefore, an object of my invention, generally stated, to provide a slider shoe which shall have a relatively long life, shall be of relatively light weight, and which may be readily and economically manufactured and installed in opera tive position.

The principal object of my invention isto provide for increasing the life and reducing the cost of manufacture of slider shoes used in currentcollecting apparatus. 7

Another object of my invention is to provide for increasing the wearing qualities of a slider shoe. 7

Still another object .of my invention is to provide, for the inclusion of a metallic insert of relatively hard material so that a minimum of machining will be required in the manufacture of slider shoes. 7

Other objects of my invention will in part be obvious and in part appear hereinafter.

My invention, accordingly, is disclosed in the drawing and comprises the feature of construction, combination of elements, and arrangement of parts, which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of my invention, reference may be had to the following detailed description, taken in connection with the accompanying draw-. ing, in which:

Figure 1 is a View in side elevation of one modification of my improved slider shoe;

Fig. 2 is a sectional View taken along the line IIII of Fig. 1; and

Figs. 3 through 8 are views in side elevation, certain parts being broken away to more clearly show the construction, and sectional views showing the various stepsin the manufacture of a preferred embodiment of my invention.

Referring now more particularly to Figs. 1 and 2 of the drawing, the reference character In designates, generally, the main body member of a slider shoe having upstanding lips ll, between which a groove 12 is formed. The main body 55 member ID is preferably a drop forging of relatively low carbon content, so that it may be readily forged and machined. It may be drop forged to form the lips II and the relatively shallow groove I 2, together with the ears I3, through which openings I4 may be drilled to provide a mounting for the slider shoe, as will be readily understood.

The main body member I9, after it comes from the drop-forging operation, is placed in a machine, such as a milling cutter, and a groove I5, of which the line I6 represents the bottom line, is machined therein.

In order to increase the wearing qualities of the slider shoe, the groove I5 is filled with a relatively hard metal I1, such as a tungsten alloy or the like. The metal I! is preferably fused into the groove I5 by means of an electric arc, the metal which is to be fused being one of the electrodes of the arc circuit, while the main body member ID constitutes the other electrode. In this manner, a very intimate engagement may be had between the relatively hard material I! and the relatively soft material of the main body member ID.

In order to provide a satisfactory slider shoe, it is desirable to fill the groove I5 up to the bottom of the original groove I2, as illustrated. It is then necessary to grind the bottom of the groove I2 to a shape indicated by the dotted line I8 in order to remove certain impurities and irregularities remaining after the fusing operation has been performed.

While the slider shoe, illustrated in Figs. 1 and 2 and described hereinbefore, is satisfactory for operation, and has a relatively long life, it is comparatively expensive to manufacture. It is particularly difficult to fuse the relatively hard material I! in the groove I5 for the reason that the bottom thereof, as represented by the line I6, is curved and open at the ends. In addition, the alloys which are used for the relatively hard material I! are very diincult, if not impossible, to machine, and, therefore, it is necessary to grind them to the shape represented by the dotted line I8. The fusing and grinding operations require considerable time and the use of costly equipment. and, as a result, the expense involved in manufacturing a slider shoe of this type is relatively high.

In order to obviate these difficulties and to reduce the expense involved in the manufacture of a slider shoe as illustrated in Figs. 1 and 2, and as set forth hereinbefore, the preferred construction shown in Figs. 3 through 8 may be used. In the preferred embodiment of the invention the main body member ID may be a drop forging similar to that described hereinbefore having the lips II, the shallow groove I2 and the depending ears I3 formed integrally therewith.

However, instead of machining a groove in the bottom of the shallow groove I2, a groove I9 may be out along the under-surface of the main body member I0 between the lips I I and the ears I3, as illustrated.

It will be observed in Figs. 3 and 4 of the drawing that the groove I9 is cut on the underside of the main body III as the first operation after the drop-forging operation. The groove I9 is preferably of limited extent, so that an appreciable amount of material will remain at the ends thereof, as illustrated. It is also desirable to form the groove I2 relatively shallow and to provide a considerable thickness between the adjacent surfaces of the grooves I2 and I9.

The relatively hard material I! may then be readily fused into the groove I9, as is illustrated in Figs. 5 and 6 of the drawing. It will be apparent that the relatively hard material I! may be readily fused in the groove I9 for the reason that the ends of the groove I9 are closed, and all that is necessary to be done is to puddle the metal I1 from the welding electrode in the groove I9 and let it flow freely until it is filled to the desired extent.

It will be apparent that the relatively great thickness between the grooves I2 and I9 is desirable in order to provide a maximum of material around the groove I9 to carry away the heat and relieve the stresses that may be set up during the fusing of the material IT, as described. Since the main body member I9 is of a relatively soft material, which may be readily machined,

it isnot objectionable to provide this relatively thick portion of material between grooves I2 and I9.

The finished slider shoe is illustrated in Figs. '7 and 8 of the drawing. As shown, the groove I2 is further machined to a surface represented by the line 20, which leaves a relatively small amount of parent material over the hard material I! in the groove I9. In addition, the sides of the main body member ID may be machined to the outline indicated, and the openings I4 may be drilled in order to provide for the mounting of the slider shoe.

When the new slider shoe is first placed in operation, the surface represented by the line 20 will be in engagement with the conductor. Due to the fact that the main body member I0 is of relatively soft metal, the bottom of the groove I2, as represented by the line 29, will rapidly wear to a surface represented by the dotted line 2I, at which time the relatively hard material I! will engage the conductor. It will then be apparent that the slider shoe will automatically provide a satisfactory contact surface for engaging the conductor after it has been in operation for a relatively short time.

It is particularly pointed out that it is unnecessary to perform any machining or grinding on the hardened material I7 when it is located in the groove I9 on the under-surface of the main body member III for the reason that any impurities or irregularities remaining after the fusing operation are on the underside of the slider shoe and hence do not provide an undesirable surface for engagement with a conductor. This positioning of the relatively hard material I! obviously reduces the cost of manufacture of the slider shoe to a marked degree and yet provides a slider shoe which includes all of the advantages of the devices of this type that have previously been used.

As the slider shoe wears in service to provide a surface represented by the line 2|, it will be apparent that the metal forming the ends of the groove I9 may serve to some extent as a lubricant, since this material is relatively soft.

Since certain further changes may be made in the above construction, and different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter contained in the above description, or shown in the accompanying drawing, shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. A slider shoe for use in collecting current from a conductor comprising, in combination, a main body member comprising relatively soft metal having a pair of upstanding lips forming a groove therebetween for engaging the conductor, and means comprising a relatively hard metal fused to the under surface of said main body member and disposed to provide a wear resisting surface for engagement with the conductor to increase the wearing qualities of the slider shoe.

2. A slider shoe for use in collecting current from a conductor comprising, in combination, a main body member comprising relatively soft metal and provided with a pair of upstanding lips and having a longitudinally extending groove on the underside thereof, and a filling of relatively hard metal fused in said groove to provide a wear resisting surface for engagement with the conductor.

3. A slider shoe for use in collecting current from a conductor comprising, in combination, a main body member comprising relatively soft metal and provided with a pair of upstanding lips and having a longitudinally extending groove of limited extent on the underside thereof, and a filling of relatively hard metal fused in said groove to provide a wear resisting surface for engagement with the conductor.

4. A slider shoe for use in collecting current from a conductor for an electric vehicle comprising, in combination, a main body member comprising relatively soft metal, a pair of upstanding lips integrally formed with the main body member and forming a groove therebetween for engagement with the conductor, said main body member being provided on the under surface with a longitudinally extending groove, and a filling of relatively hard metal fused in said groove on the under surface to provide a wear resisting surface for engagement with the conductor after the metal of the groove between the upstanding lips has been worn through.

5. A slider shoe for use in collecting current from a conductor for an electric Vehicle comprising, in combination, a main body member comprising relatively soft metal, a pair of upstanding lips integrally formed with the main body member and forming a groove therebetween for engagement with the conductor, said main body member being provided on the under surface with a longitudinally extending groove of limited extent centrally disposed relative to the groove between the upstanding lips, and a filling of relatively hard metal fused in said groove on the under surface to provide a wear resisting surface for engagement with the conductor after the metal of the groove between the upstanding lips has been worn through.

6. The method of manufacturing a slider shoe for collecting current from a conductor which comprises forming a slider shoe from relatively soft metal with a longitudinally extending groove on the underside extending up into the wear portion of the shoe, and using a relatively hard metal in the groove to form a wearing portion.

7. The method of manufacturing a slider shoe for collecting current from a conductor which comprises forming a slider shoe from a relatively soft metal, providing a groove on the underside of limited extent extending up into the wear portion of the shoe, and fusing a relatively hard metal into said groove by means of an electric arc to form a wear portion.

8. The method of manufacturing a slider shoe for collecting current from a conductor which comprises forming a slider shoe having a thickened main body member of relatively soft metal, providing a groove on the underside extending up into the wear portion of the shoe, fusing a relatively hard metal into said groove by means of an electric arc to form a wear portion, and removing a portion of said thickened main body member to provide a groove for the conductor.

9. The method of manufacturing a slider shoe for collecting current from a conductor which comprises forming a slider shoe having a thickened main body member of relatively soft metal, providing a groove of limited extent on the underside extending up into the wear portion of the shoe, fusing a relatively hard metal into said groove to form a wear portion, and removing aportion of said thickened main body member over the fused hard metal to provide a groove for the conductor.

NILS A. WAHLBER'G. 

